From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Herland Subject: [PATCH] quickfetch(): Prevent overflow of the rev-list command line Date: Thu, 09 Jul 2009 11:34:45 +0200 Message-ID: <200907091134.45492.johan@herland.net> References: <200907091107.46838.johan@herland.net> <4A55B54D.4080601@viscovery.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: 7BIT Cc: git@vger.kernel.org, Peter Krefting , "Shawn O. Pearce" , Alex Riesen To: Johannes Sixt , Junio C Hamano X-From: git-owner@vger.kernel.org Thu Jul 09 11:34:58 2009 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1MOq1n-0000V3-Tq for gcvg-git-2@gmane.org; Thu, 09 Jul 2009 11:34:56 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753938AbZGIJev (ORCPT ); Thu, 9 Jul 2009 05:34:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753532AbZGIJeu (ORCPT ); Thu, 9 Jul 2009 05:34:50 -0400 Received: from mx.getmail.no ([84.208.15.66]:53442 "EHLO get-mta-out02.get.basefarm.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752181AbZGIJet (ORCPT ); Thu, 9 Jul 2009 05:34:49 -0400 Content-disposition: inline Received: from mx.getmail.no ([10.5.16.4]) by get-mta-out02.get.basefarm.net (Sun Java(tm) System Messaging Server 7.0-0.04 64bit (built Jun 20 2008)) with ESMTP id <0KMI00612D9Z3G50@get-mta-out02.get.basefarm.net> for git@vger.kernel.org; Thu, 09 Jul 2009 11:34:47 +0200 (MEST) Received: from alpha.localnet ([84.215.102.95]) by get-mta-in02.get.basefarm.net (Sun Java(tm) System Messaging Server 7.0-0.04 64bit (built Jun 20 2008)) with ESMTP id <0KMI003FKD9XD390@get-mta-in02.get.basefarm.net> for git@vger.kernel.org; Thu, 09 Jul 2009 11:34:46 +0200 (MEST) X-PMX-Version: 5.5.3.366731, Antispam-Engine: 2.7.0.366912, Antispam-Data: 2009.7.9.92417 User-Agent: KMail/1.11.4 (Linux/2.6.30-ARCH; KDE/4.2.4; x86_64; ; ) In-reply-to: <4A55B54D.4080601@viscovery.net> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: quickfetch() calls rev-list to check whether the objects we are about to fetch are already present in the repo (if so, we can skip the object fetch). However, when there are many (~1000) refs to be fetched, the rev-list command line grows larger than the maximum command line size on some systems (32K in Windows). This causes rev-list to fail, making quickfetch() return non-zero, which unnecessarily triggers the transport machinery. This somehow causes fetch to fail with an exit code. By using the --stdin option to rev-list (and feeding the object list to its standard input), we prevent the overflow of the rev-list command line, which causes quickfetch(), and subsequently the overall fetch, to succeed. However, using rev-list --stdin is not entirely straightforward: rev-list terminates immediately when encountering an unknown object, which can trigger SIGPIPE if we are still writing object's to its standard input. We therefore ignore SIGPIPE so that the fetch process is not terminated. Signed-off-by: Johan Herland Improved-by: Johannes Sixt Improved-by: Alex Riesen Tested-by: Peter Krefting --- builtin-fetch.c | 62 +++++++++++++++++++++++++++++++------------------------ 1 files changed, 35 insertions(+), 27 deletions(-) diff --git a/builtin-fetch.c b/builtin-fetch.c index cd5eb9a..20bcbdd 100644 --- a/builtin-fetch.c +++ b/builtin-fetch.c @@ -400,14 +400,14 @@ static int store_updated_refs(const char *raw_url, const char *remote_name, /* * We would want to bypass the object transfer altogether if - * everything we are going to fetch already exists and connected + * everything we are going to fetch already exists and is connected * locally. * - * The refs we are going to fetch are in to_fetch (nr_heads in - * total). If running + * The refs we are going to fetch are in ref_map. If running * - * $ git rev-list --objects to_fetch[0] to_fetch[1] ... --not --all + * $ git rev-list --objects --stdin --not --all * + * (feeding all the refs in ref_map on its standard input) * does not error out, that means everything reachable from the * refs we are going to fetch exists and is connected to some of * our existing refs. @@ -416,8 +416,9 @@ static int quickfetch(struct ref *ref_map) { struct child_process revlist; struct ref *ref; - char **argv; - int i, err; + int err; + const char *argv[] = {"rev-list", + "--quiet", "--objects", "--stdin", "--not", "--all", NULL}; /* * If we are deepening a shallow clone we already have these @@ -429,34 +430,41 @@ static int quickfetch(struct ref *ref_map) if (depth) return -1; - for (i = 0, ref = ref_map; ref; ref = ref->next) - i++; - if (!i) + if (!ref_map) return 0; - argv = xmalloc(sizeof(*argv) * (i + 6)); - i = 0; - argv[i++] = xstrdup("rev-list"); - argv[i++] = xstrdup("--quiet"); - argv[i++] = xstrdup("--objects"); - for (ref = ref_map; ref; ref = ref->next) - argv[i++] = xstrdup(sha1_to_hex(ref->old_sha1)); - argv[i++] = xstrdup("--not"); - argv[i++] = xstrdup("--all"); - argv[i++] = NULL; - memset(&revlist, 0, sizeof(revlist)); - revlist.argv = (const char**)argv; + revlist.argv = argv; revlist.git_cmd = 1; - revlist.no_stdin = 1; revlist.no_stdout = 1; revlist.no_stderr = 1; - err = run_command(&revlist); + revlist.in = -1; + + /* If rev-list --stdin encounters an unknown commit, it terminates, + * which will cause SIGPIPE in the write loop below. */ + signal(SIGPIPE, SIG_IGN); + + err = start_command(&revlist); + if (err) { + error("could not run rev-list"); + return err; + } - for (i = 0; argv[i]; i++) - free(argv[i]); - free(argv); - return err; + for (ref = ref_map; ref; ref = ref->next) { + if (write_in_full(revlist.in, sha1_to_hex(ref->old_sha1), 40) < 0 || + write_in_full(revlist.in, "\n", 1) < 0) { + err = errno; + if (err != EPIPE && err != EINVAL) + error("failed write to rev-list"); + break; + } + } + + if (close(revlist.in)) { + err = errno; + error("failed to close rev-list's stdin"); + } + return finish_command(&revlist) || err; } static int fetch_refs(struct transport *transport, struct ref *ref_map) -- 1.6.3.rc0.1.gf800